Generally compressor systems are equipped with chillers and separators to remove at least some of the moisture entrained in the flow of the gas being compressed. Removing moisture from the gas being compressed reduces the work necessary to compress the gas and mitigates corrosion and moisture build up in downstream equipment supplied by the compressor system. The chiller reduces the temperature of the compressed gas, thus promoting the formation of condensation from the compressed gas as it enters the inlet of the separator. The separator causes the liquid condensate to settle to the bottom of the separator vessel while the compressed gas exits the separator above the inlet.
Condensate that has accumulated in the separator must be drained away to prevent it from backing up into the flow of compressed gas. However, the draining of the condensate must be controlled to prevent compressed gas from leaking from the system via the drain path, thereby reducing the efficiency of the compressor system. Typically, at least a small amount of condensate remaining in the bottom of the separator is desired to block the potential leak path out of the drain.
Two conventional means of controlling the draining of the condensate include timed solenoid systems and so-called no-loss systems. Timed solenoid systems open and close a drain valve downstream of the separator at predetermined intervals set by an operator. Such systems may include a high level sensor to shut down the compressor system if the condensate overfills the separator volume. Because the drain interval is set by an operator, the predetermined drain interval may not be appropriate for changing operating conditions, resulting in poor drainage. No-loss systems attempt to overcome this deficiency by controlling the flow of condensate through a separate reservoir connected to the bottom of the separator. However, such systems have proven unreliable. And, because the drain valve of the conventional no-loss system is not directly tied to a level sensor in the separator, a back-up drain valve is often needed, which increases costs. Therefore, further technological developments are desirable in this area.